Can't start/rewind Episode 4 (Black Screen)

I finished episode 4 of the game recently. But after I started episode 5, my choices of the 4th episode didn't save. So I restarted the game but the problem still exists.Then I tried to rewind the 4th episode , but I stucked in a black screen. I can only move my mouse or force quit the game.

thanks for your reply.I tried the steps but unfortunately it doesn't work.

When I try to rewind episode 4, I can only choose "Chapter 6: For Whom The Bells Tolls" as latest chapter. So I think the rest is deleted. But when I try to rewind, I still get a black screen.What can I do to fix the black screen ?